The Cleveland Clinic Foundation and the Lewis Research Center, NASA, want to initiate a joint project to determine the usefulness of Fast Neutron Therapy in the treatment of malignant tumors. The principal objectives of this proposal are as follows: (A) To adapt the Lewis Research Center's variable energy cyclotron for Fast Neutron Radiotherapy, and (B) To contribute as many patients as possible to the on-going clinical trials in similar installations throughout the United States (Washington, D.C.; Houston, Texas; Seattle, Washington). Furthermore, the Neutron Beam will be provided to Biophysicists, Biologists, and Physicians for the purpose of establishing biological response. Comparison will be made between the Neutron Beam of this installation from the physical point-of-view, as well as from the radiobiological point-of-view, and other installations throughout the United States. METHODS: The Great Lakes Area Neutron Treatment Association will include all the major medical centers in Ohio, Western Pennsylvania, and Eastern Indiana. These medical centers will provide patients suitable for Neutron treatment and they will be referred to The Cleveland Clinic Foundation where they will be worked-up from the radiotherapeutic point-of-view following the guidelines of the protocols available at other institutions utilizing Neutrons and actually sponsored by the National Cancer Institite. The patients will be transported by bus to the Lewis Research Center, NASA, which is about 25 minutes from The Cleveland Clinic Hospital, where they will receive the treatments.